+function isMatchingBracket(open, close) {
+  const bracketPairs = {
+    '(': ')', 
+    '[': ']', 
+    '{': '}'
+  };
+  return bracketPairs[open] === close;
+}
+
 function solution3(s) {
   let answer = 0;
   const sList = [...s, ...s];
   for (let start = 0; start < s.length; start++) {
     const stack = [];
     let isValid = true;
     for (let offset = 0; offset < s.length; offset++) {
       const c = sList[start + offset];
-      if (c === "(" || c === "[" || c === "{") {
+      if ("([{".includes(c)) {
         stack.push(c);
       } else {
         const top = stack.pop();
-        if (!top) {
+        if (!top || !isMatchingBracket(top, c)) {
           isValid = false;
           break;
         }
-        if (top === "(" && c === ")") continue;
-        if (top === "[" && c === "]") continue;
-        if (top === "{" && c === "}") continue;
-        isValid = false;
-        break;
       }
     }
     if (isValid && stack.length === 0) answer++;
   }
   return answer;
 }

 function solution2(s) {
   const stack = [];
   for (const c of s) {
-    if (stack.length === 0) {
-      stack.push(c);
-      continue;
-    }
-    const top = stack[stack.length - 1];
-    if (c === top) {
+    if (stack.length > 0 && stack[stack.length - 1] === c) {
       stack.pop();
     } else {
       stack.push(c);
     }
   }
 
   return stack.length === 0 ? 1 : 0;
 }